The use of systems for heating and dispensing hot water is known in the market place. As used herein, "hot" refers to temperatures at or about 190.degree. Fahrenheit (88.degree. Celsius), but below the boiling point of water (212.degree. Fahrenheit/100.degree. Celsius). Water at this high temperature can be made available at a dedicated faucet for users needing hot water to make, for example, coffee, tea or cocoa. A typical preexisting system heats water in a relatively small tank that is situated below the sink on which the dedicated faucet is mounted. The tank may have a capacity of 1/3 or 1/2 gallons (1.3 or 1.9 liters). Such tanks are usually divided into two chambers, a main chamber and an expansion chamber. Water is heated electrically in the main chamber. The expansion chamber is contiguous with the main chamber and contains water that is initially heated in the main chamber and allowed to expand into the expansion chamber to preclude pressure buildup generated by heating the water.
Most known water heating chambers and tanks utilize metal fabricating wherein several pieces of metal must be integrated together to create separate air and watertight chambers. This metal construction is labor intensive, requires expensive cleaning operations during fabrication and is susceptible to leaks.
Most established metal tank systems utilize a temperature sensing system attached to the outside of a metal tank to directly sense the water temperature. The temperature of the metal on the outside of a hot water heating tank will register nearly the same temperature as the water inside the tank because metal conducts heat extremely well. Such temperature sensing systems would not effectively perform in the same manner with a plastic tank construction because a plastic tank does not efficiently conduct heat.
Accordingly, a need exists for a plastic water-heating tank with an exterior temperature sensing system that accurately and efficiently determines the water temperature inside the tank and adjusts that temperature accordingly.